Common ESD problems on factory sites
In many factories, they use a lot of anti-static products, why do static electricity problems often occur? The following are common wrong anti-static concepts and wrong anti-static product usage methods during factory inspections.
1. No anti-static product testing instruments
The most common mistake is that many companies purchase a lot of anti-static products, but do not purchase some commonly used anti-static product testing instruments. We know that each product has a certain service life and the quality is good or bad. If there are no commonly used testing instruments, we don't know whether the product is damaged or the quality is good. This will not have an anti-static effect.
2. Poor ground connection method
a. The anti-static system must have an independent and reliable grounding device. The grounding resistance should generally be less than 10Ω, and the burial and detection methods should comply with the requirements of GBJ 97.
b. The anti-static ground wire must not be connected to the power supply neutral wire and must not be shared with the lightning protection ground wire. Because lightning strikes and other phenomena will affect the performance of the product and personal safety through the loop.
c. Use a three-phase five-wire power supply, and its large ground wire can be used as an anti-static ground wire (but the neutral wire and ground wire must not be mixed).
d. The cross-sectional area of the grounding trunk line should be no less than 100mm2; the cross-sectional area of the branch line should be no less than 6mm2; the grounding wire of the equipment and workbench should use a multi-strand plastic-coated wire with a cross-sectional area of no less than 1.25mm2, and the color of the grounding wire should be yellow-green.
e. The connection method of the grounding trunk line should be brazing.
f. The connection terminals of the anti-static equipment should ensure reliable contact and easy installation and disassembly. Various clip-type connectors are allowed, such as fish clips, plug sockets, etc.
g. The workplace with high requirements for grounding resistance value should install a grounding system monitoring alarm.